Make AttachmentService accessible directly from

SyncableService without having to have SyncData.

Added a new method SetAttachmentService to SyncableService
interface. It should be implemented by a syncable service that
supports attachments. By default this method does nothing.

This method is called SharedChangeProcessor when it gets
connected to an attachment enabled syncable service (which
provides a non-default implementation GetAttachmentStore).

Added a new test case that tests attachment specific
integration code in GenericChangeProcessor and SyncableService.

BUG=439510

Review URL: https://codereview.chromium.org/769913003

Cr-Commit-Position: refs/heads/master@{#307520}

4 files changed, 46 insertions, 0 deletions

diff --git a/sync/api/fake_syncable_service.cc b/sync/api/fake_syncable_service.cc
index 0d76f2e..ec7b90c 100644
--- a/sync/api/fake_syncable_service.cc
+++ b/sync/api/fake_syncable_service.cc
@@ -25,6 +25,15 @@ void FakeSyncableService::set_process_sync_changes_error(
   process_sync_changes_error_ = error;
 }
 
+void FakeSyncableService::set_attachment_store(
+    const scoped_refptr<AttachmentStore>& attachment_store) {
+  attachment_store_ = attachment_store;
+}
+
+const AttachmentService* FakeSyncableService::attachment_service() const {
+  return attachment_service_.get();
+}
+
 bool FakeSyncableService::syncing() const {
   return syncing_;
 }
@@ -61,4 +70,13 @@ SyncError FakeSyncableService::ProcessSyncChanges(
   return process_sync_changes_error_;
 }
 
+scoped_refptr<AttachmentStore> FakeSyncableService::GetAttachmentStore() {
+  return attachment_store_;
+}
+
+void FakeSyncableService::SetAttachmentService(
+    scoped_ptr<AttachmentService> attachment_service) {
+  attachment_service_ = attachment_service.Pass();
+}
+
 }  // namespace syncer
diff --git a/sync/api/fake_syncable_service.h b/sync/api/fake_syncable_service.h
index 8ecf05e..7403ef3 100644
--- a/sync/api/fake_syncable_service.h
+++ b/sync/api/fake_syncable_service.h
@@ -22,6 +22,14 @@ class FakeSyncableService : public SyncableService {
   void set_merge_data_and_start_syncing_error(const SyncError& error);
   void set_process_sync_changes_error(const SyncError& error);
 
+  // Setter for AttachmentStore.
+  void set_attachment_store(
+      const scoped_refptr<AttachmentStore>& attachment_store);
+
+  // AttachmentService should be set when this syncable service is connected,
+  // just before MergeDataAndStartSyncing. NULL is returned by default.
+  const AttachmentService* attachment_service() const;
+
   // Whether we're syncing or not. Set on a successful MergeDataAndStartSyncing,
   // unset on StopSyncing. False by default.
   bool syncing() const;
@@ -36,6 +44,9 @@ class FakeSyncableService : public SyncableService {
   SyncDataList GetAllSyncData(ModelType type) const override;
   SyncError ProcessSyncChanges(const tracked_objects::Location& from_here,
                                const SyncChangeList& change_list) override;
+  scoped_refptr<AttachmentStore> GetAttachmentStore() override;
+  void SetAttachmentService(
+      scoped_ptr<AttachmentService> attachment_service) override;
 
  private:
   scoped_ptr<SyncChangeProcessor> sync_processor_;
@@ -43,6 +54,8 @@ class FakeSyncableService : public SyncableService {
   SyncError process_sync_changes_error_;
   bool syncing_;
   ModelType type_;
+  scoped_refptr<AttachmentStore> attachment_store_;
+  scoped_ptr<AttachmentService> attachment_service_;
 };
 
 }  // namespace syncer
diff --git a/sync/api/syncable_service.cc b/sync/api/syncable_service.cc
index 9d4773c..7b0a973 100644
--- a/sync/api/syncable_service.cc
+++ b/sync/api/syncable_service.cc
@@ -12,4 +12,8 @@ scoped_refptr<AttachmentStore> SyncableService::GetAttachmentStore() {
   return scoped_refptr<AttachmentStore>();
 }
 
+void SyncableService::SetAttachmentService(
+    scoped_ptr<AttachmentService> attachment_service) {
+}
+
 }  // namespace syncer
diff --git a/sync/api/syncable_service.h b/sync/api/syncable_service.h
index 17feb63..960abc5 100644
--- a/sync/api/syncable_service.h
+++ b/sync/api/syncable_service.h
@@ -21,6 +21,7 @@
 
 namespace syncer {
 
+class AttachmentService;
 class SyncErrorFactory;
 
 // TODO(zea): remove SupportsWeakPtr in favor of having all SyncableService
@@ -76,6 +77,16 @@ class SYNC_EXPORT SyncableService
   // to return pointer to it.
   virtual scoped_refptr<AttachmentStore> GetAttachmentStore();
 
+  // Called by sync to provide AttachmentService to be used to download
+  // attachments.
+  // SetAttachmentService is called after GetAttachmentStore and right before
+  // MergeDataAndStartSyncing and only if GetAttachmentStore has returned a
+  // non-NULL store instance. Default implementation does nothing.
+  // Datatype that uses attachments must take ownerhip of the provided
+  // AttachmentService instance.
+  virtual void SetAttachmentService(
+      scoped_ptr<AttachmentService> attachment_service);
+
  protected:
   ~SyncableService() override;
 };